use std::collections::HashMap;
use std::path::PathBuf;
use std::sync::Arc;

use codex_core::Codex;
use codex_core::codex_wrapper::init_codex;
use codex_core::config::Config as CodexConfig;
use codex_core::config::ConfigOverrides;
use codex_core::protocol::EventMsg;
use codex_core::protocol::SessionConfiguredEvent;
use mcp_types::RequestId;
use tokio::sync::Mutex;
use uuid::Uuid;

use crate::conversation_loop::run_conversation_loop;
use crate::json_to_toml::json_to_toml;
use crate::mcp_protocol::ConversationCreateArgs;
use crate::mcp_protocol::ConversationCreateResult;
use crate::mcp_protocol::ConversationId;
use crate::mcp_protocol::ToolCallResponseResult;
use crate::message_processor::MessageProcessor;

pub(crate) async fn handle_create_conversation(
    message_processor: &MessageProcessor,
    id: RequestId,
    args: ConversationCreateArgs,
) {
    // Build ConfigOverrides from args
    let ConversationCreateArgs {
        prompt: _, // not used here; creation only establishes the session
        model,
        cwd,
        approval_policy,
        sandbox,
        config,
        profile,
        base_instructions,
    } = args;

    // Convert config overrides JSON into CLI-style TOML overrides
    let cli_overrides: Vec<(String, toml::Value)> = match config {
        Some(v) => match v.as_object() {
            Some(map) => map
                .into_iter()
                .map(|(k, v)| (k.clone(), json_to_toml(v.clone())))
                .collect(),
            None => Vec::new(),
        },
        None => Vec::new(),
    };

    let overrides = ConfigOverrides {
        model: Some(model.clone()),
        cwd: Some(PathBuf::from(cwd)),
        approval_policy,
        sandbox_mode: sandbox,
        model_provider: None,
        config_profile: profile,
        codex_linux_sandbox_exe: None,
        base_instructions,
        include_plan_tool: None,
        disable_response_storage: None,
        show_raw_agent_reasoning: None,
    };

    let cfg: CodexConfig = match CodexConfig::load_with_cli_overrides(cli_overrides, overrides) {
        Ok(cfg) => cfg,
        Err(e) => {
            message_processor
                .send_response_with_optional_error(
                    id,
                    Some(ToolCallResponseResult::ConversationCreate(
                        ConversationCreateResult::Error {
                            message: format!("Failed to load config: {e}"),
                        },
                    )),
                    Some(true),
                )
                .await;
            return;
        }
    };

    // Initialize Codex session
    let codex_conversation = match init_codex(cfg).await {
        Ok(conv) => conv,
        Err(e) => {
            message_processor
                .send_response_with_optional_error(
                    id,
                    Some(ToolCallResponseResult::ConversationCreate(
                        ConversationCreateResult::Error {
                            message: format!("Failed to initialize session: {e}"),
                        },
                    )),
                    Some(true),
                )
                .await;
            return;
        }
    };

    // Expect SessionConfigured; if not, return error.
    let EventMsg::SessionConfigured(SessionConfiguredEvent { model, .. }) =
        &codex_conversation.session_configured.msg
    else {
        message_processor
            .send_response_with_optional_error(
                id,
                Some(ToolCallResponseResult::ConversationCreate(
                    ConversationCreateResult::Error {
                        message: "Expected SessionConfigured event".to_string(),
                    },
                )),
                Some(true),
            )
            .await;
        return;
    };

    let effective_model = model.clone();

    let session_id = codex_conversation.session_id;
    let codex_arc = Arc::new(codex_conversation.codex);

    // Store session for future calls
    insert_session(
        session_id,
        codex_arc.clone(),
        message_processor.session_map(),
    )
    .await;
    // Run the conversation loop in the background so this request can return immediately.
    let outgoing = message_processor.outgoing();
    let spawn_id = id.clone();
    tokio::spawn(async move {
        run_conversation_loop(codex_arc.clone(), outgoing, spawn_id).await;
    });

    // Reply with the new conversation id and effective model
    message_processor
        .send_response_with_optional_error(
            id,
            Some(ToolCallResponseResult::ConversationCreate(
                ConversationCreateResult::Ok {
                    conversation_id: ConversationId(session_id),
                    model: effective_model,
                },
            )),
            Some(false),
        )
        .await;
}

async fn insert_session(
    session_id: Uuid,
    codex: Arc<Codex>,
    session_map: Arc<Mutex<HashMap<Uuid, Arc<Codex>>>>,
) {
    let mut guard = session_map.lock().await;
    guard.insert(session_id, codex);
}